The subject matter disclosed herein relates to appliances using a mechanical refrigeration cycle, and more particularly to heat pump dryers and the like.
Clothes dryers have typically used electric resistance heaters or gas burners to warm air to be used for drying clothes. These dryers typically work on an open cycle, wherein the air that has passed through the drum and absorbed moisture from the clothes is exhausted to ambient. More recently, there has been interest in heat pump dryers operating on a closed cycle, wherein the air that has passed through the drum and absorbed moisture from the clothes is dried, re-heated, and re-used.
Challenges exist in reducing the time constant to full capacity at start-up that is inherent in heat pump dryers. Existing approaches, attempt to use an auxiliary heater to gently add load and bring about a slow rise in the system equilibrium point during the run cycle.